Add VMServiceScrape configuration for CockroachDB monitoring

[cuisongliu]

This pull request adds support for VictoriaMetrics monitoring by introducing VMServiceScrape resources and corresponding configuration options, alongside improvements to the existing Prometheus ServiceMonitor setup. The main changes include new Helm templates for VictoriaMetrics, configuration options in values.yaml, and the addition of service monitoring for the optional Visus component.

VictoriaMetrics monitoring support:

• Added a new Helm template vmServiceScrape.yaml to generate VMServiceScrape resources for VictoriaMetrics Operator, enabling metrics scraping from CockroachDB and the optional Visus service. This includes support for custom labels, annotations, intervals, namespace scoping, and TLS configuration.
• Introduced a new vmServiceScrape configuration section in values.yaml to control the VictoriaMetrics monitoring feature, with options for enabling, labeling, annotating, and configuring scrape intervals and TLS.

Prometheus ServiceMonitor improvements:

• Enhanced the existing serviceMonitor.yaml template to add a ServiceMonitor for the Visus component when enabled, mirroring the main CockroachDB monitoring setup.
• Improved TLS configuration handling in serviceMonitor.yaml for Visus endpoints by correcting the conditional logic and indentation, ensuring proper rendering when TLS is enabled and Visus is not in insecure mode.